Quantification of the evolution of the 3D intermetallic structure in a 6005A aluminium alloy during a homogenisation treatment

Kuijpers, N.C.W.; Tirel, J.; Hanlon, D. N.; Zwaag, Sybrand van der

doi:10.1016/s1044-5803(02)00289-9

Cited by 70 publications

(35 citation statements)

References 7 publications

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“…Insoluble or undissolved intermetallic particles and dispersoids, such as ß-Al 5 FeSi, α-Al 15 (FeMn) 3 Si and α-Al 12 (Fe,Mn) 3 Si, which form during solidification or homogenisation, can be present in Al-Mg-Si type alloys with Mn and Fe additions and impurities [67,79,80,81,82,83,84]. The SEM micrograph in Fig.…”

Section: Acknowledgementsmentioning

confidence: 99%

A model for the thermodynamics of and strengthening due to co-clusters in Al–Mg–Si-based alloys

2012

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An expanded model for the thermodynamics of co-clusters and their strengthening is presented, and the model is applied to predict co-cluster formation and strengthening in AlMg-Si alloys. The models are tested against data on a wide range of Al-Mg-Si alloys aged at room temperature. The strengthening due to co-clusters is predicted well. The formation of the co-clusters is studied in an Al-0.5at%Mg-1at%Si alloy using three-dimensional atom probe analysis. The results correspond well with the model. It is shown that in general, (shortrange) order strengthening due to co-clusters will be the main strengthening mechanism in these alloys. Apart from the co-clusters, Si clusters also form, but due to their low enthalpy of formation, they contribute little to the strength.

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Section: Acknowledgementsmentioning

confidence: 99%

A model for the thermodynamics of and strengthening due to co-clusters in Al–Mg–Si-based alloys

2012

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“…During this homogenisation process, at temperatures between 530-600 C, 1) plate-like monoclinic intermetallic -Al 5 FeSi particles transform to multiple rounded -Al 12 (Fe x Mn ð1ÀxÞ ) 3 Si particles. [2][3][4] This phase transformation improves the processability of the aluminium considerably. The plate-like -particles can lead to local crack initiation and induce surface defects on the extruded material.…”

Section: Introductionmentioning

confidence: 99%

“…Some of the particles observed were facetted whereas others exhibited a more rounded morphology. During the transformation, theAlFeSi phase is observed to remain plate-like with an approximately constant thickness, 4) leading to the conclusion that the plate only dissolves at the rim, injecting Fe and Si into the Al-matrix. At a later stage of the transformation, the particles will grow as spheres with possibly fingering as a side-effect.…”

Section: Introductionmentioning

confidence: 99%

A Model of the β-AlFeSi to α-Al(FeMn)Si Transformation in Al-Mg-Si Alloys

Kuijpers¹,

Vermolen

Vuik

et al. 2003

Mater. Trans.

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During the homogenisation process of Al-Mg-Si extrusion alloys, plate-like -Al 5 FeSi particles transform to multiple roundedAl 12 (FeMn) 3 Si particles. The rate of this to transformation determines the time which is required to homogenise the aluminium sufficiently for extrusion. In this paper, a finite element approach is presented which model the development of fraction transformed with time, in the beginning of the transformation, as a function of homogenisation temperature, as-cast microstructure and concentration of alloying elements. We treat the to transformation mathematically as a Stefan problem, where the concentration and the position of the moving boundaries of the and particles are determined. For the boundary conditions of the model thermodynamic calculations are used (Thermo-Calc). The influence of several process parameters on the modelled transformed fraction, such as the temperature and initial thickness of the plates, are investigated. Finally the model is validated with experimental data.

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“…The fact that there is no further reduction of the aspect ratio between 4 and 6 h homogenization, discussed above, is attributed to the decreased connectivity of the α-AlFeSi phase, which follows the necklace formation. A continuous decrease of connectivity with homogenization time has been also observed for a 6005 Al-alloy [20]. Spheroidization and in particular, necklace formation, has been considered a key process for increased extrudability [18,19].…”

Section: Resultsmentioning

confidence: 81%

“…Mg 2 Si, α-AlFeSi, and β-AlFeSi intermetallics are located at the grain boundaries, while the α-AlFeSi phase exhibits the characteristic "Chinese-script" morphology. The morphological evolution with homogenization time is indicated in Figure 2b, [20]. Clear spheroidization of particles and necklace formation is evident only in the micrographs of Figure 2f,g, i.e., after 6 h homogenization.…”

Section: Resultsmentioning

confidence: 96%

Metallographic Index-Based Quantification of the Homogenization State in Extrudable Aluminum Alloys

Sarafoglou

Aristeidakis

Tzini

et al. 2016

Metals

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Extrudability of aluminum alloys of the 6xxx series is highly dependent on the microstructure of the homogenized billets. It is therefore very important to characterize quantitatively the state of homogenization of the as-cast billets. The quantification of the homogenization state was based on the measurement of specific microstructural indices, which describe the size and shape of the intermetallics and indicate the state of homogenization. The indices evaluated were the following: aspect ratio (AR), which is the ratio of the maximum to the minimum diameter of the particles, feret (F), which is the maximum caliper length, and circularity (C), which is a measure of how closely a particle resembles a circle in a 2D metallographic section. The method included extensive metallographic work and the measurement of a large number of particles, including a statistical analysis, in order to investigate the effect of homogenization time. Among the indices examined, the circularity index exhibited the most consistent variation with homogenization time. The lowest value of the circularity index coincided with the metallographic observation for necklace formation. Shorter homogenization times resulted in intermediate homogenization stages involving rounding of edges or particle pinching. The results indicated that the index-based quantification of the homogenization state could provide a credible method for the selection of homogenization process parameters towards enhanced extrudability.

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Quantification of the evolution of the 3D intermetallic structure in a 6005A aluminium alloy during a homogenisation treatment

Cited by 70 publications

References 7 publications

A model for the thermodynamics of and strengthening due to co-clusters in Al–Mg–Si-based alloys

A model for the thermodynamics of and strengthening due to co-clusters in Al–Mg–Si-based alloys

A Model of the β-AlFeSi to α-Al(FeMn)Si Transformation in Al-Mg-Si Alloys

Metallographic Index-Based Quantification of the Homogenization State in Extrudable Aluminum Alloys

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Quantification of the evolution of the 3D intermetallic structure in a 6005A aluminium alloy during a homogenisation treatment

Cited by 70 publications

References 7 publications

A model for the thermodynamics of and strengthening due to co-clusters in Al–Mg–Si-based alloys

A model for the thermodynamics of and strengthening due to co-clusters in Al–Mg–Si-based alloys

A Model of the &beta;-AlFeSi to &alpha;-Al(FeMn)Si Transformation in Al-Mg-Si Alloys

Metallographic Index-Based Quantification of the Homogenization State in Extrudable Aluminum Alloys

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A Model of the β-AlFeSi to α-Al(FeMn)Si Transformation in Al-Mg-Si Alloys